Packaged integrated circuit devices generally contain heat sinks or spreaders. The heat sink may be in the package and include a top layer of plated metal integral to the integrated circuit for efficient dissipation of thermal energy. In general, thermal energy is a function of power generated by an integrated circuit. Accordingly, dissipation of thermal energy is especially important in power integrated circuits, microprocessors, large digital signal processors, large area high component count integrated circuits, and the like.
To dissipate thermal energy an integrated circuit package may include a large heat sink in the form of a copper slug as an integral part of the metal lead frame to which the integrated circuit is mounted. The back of the integrated circuit may be mounted to the metal slug with either epoxy or solder. Thermal energy is transferred from the integrated circuit in the semiconductor material of the chip and then to the metal slug. A surface mounted heat sink and fan may also be used to dissipate thermal energy. Using this scheme, thermal energy is transferred from the semiconductor material up through metal and dielectric layers and ultimately through the plastic packaging to the surface mounted heat sink. A problem with these methods is that they generally require integrated circuits to operate at a relatively high temperature. Such temperatures can significantly degrade performance of the integrated circuits.